1. General Principles & Basic Science MCQs

Trunnionosis in total hip arthroplasty, characterized by wear and localized failure at the modular head-neck junction, is primarily initiated by which specific type of corrosion?

Long-term bisphosphonate therapy is associated with an increased risk of atypical subtrochanteric femur fractures. At the cellular level, how do nitrogen-containing bisphosphonates primarily alter bone metabolism?

Cortical bone exhibits significantly higher ultimate tensile strength when loaded parallel to the osteons (longitudinally) compared to when it is loaded perpendicularly (transversely). Which of the following mechanical terms best describes this direction-dependent property?

A 55-year-old postmenopausal woman is prescribed romosozumab for severe osteoporosis. Which of the following best describes the primary mechanism of action of this medication in bone remodeling?

During a biomechanical evaluation of a normal human patellar tendon, the initial non-linear "toe region" of the stress-strain curve is observed. What physiological structural property is responsible for this phenomenon?

Which zone of articular cartilage is characterized by the highest concentration of water, lowest concentration of proteoglycans, and collagen fibers oriented parallel to the joint surface?

Bone morphogenetic proteins (BMPs) play a crucial role in osteoinduction during fracture healing. Through which intracellular signaling molecules do BMPs primarily exert their osteogenic effects?

Osteoclasts resorb bone by creating an acidic microenvironment in the sealed zone. Which enzyme is primarily responsible for generating the hydrogen ions needed for this acidification process?

A viscoelastic material, such as a ligament, is subjected to a constant tensile load over an extended period, resulting in a gradual increase in length over time. This biomechanical property is defined as:

Which of the following conditions represents intramembranous ossification in the context of orthopedic fracture healing?

A surgeon implants a stainless steel screw through a titanium plate. What type of corrosion is most likely to occur due to the mixing of these dissimilar metals in the body?

Teriparatide is utilized in the management of severe osteoporosis. What is the mechanism by which it increases bone mineral density?

Nitrogen-containing bisphosphonates inhibit bone resorption primarily by inducing osteoclast apoptosis. Which specific intracellular pathway is targeted by these agents?

Increasing the inner (root) diameter of a cortical bone screw has which of the following mechanical effects?

A patient receives a regional nerve block with bupivacaine. Toxicity from systemic absorption of bupivacaine is most primarily associated with which of the following complications?

Nonsteroidal anti-inflammatory drugs (NSAIDs) are often withheld following fractures or spinal fusions due to concerns of impaired bone healing. NSAIDs interfere with bone healing primarily by inhibiting which of the following?

A 60-year-old man presents with a swollen, painful knee. Arthrocentesis yields a synovial fluid with a white blood cell count of 45,000 cells/mcL with 85% polymorphonuclear leukocytes. Under polarized light microscopy, weakly positively birefringent rhomboid crystals are seen. What is the principal composition of these crystals?

Parathyroid hormone (PTH) maintains serum calcium homeostasis via multiple organ systems. What is the direct effect of PTH on the kidneys?

Polymethylmethacrylate (PMMA) bone cement is frequently used in arthroplasty. Which of the following statements best describes the mechanical properties and function of PMMA?